Investigation of VO2 Thin Film Grown on III-Nitride Epitaxial Layer

VO2 film was incorporated with GaN microcantilevers, and proved to be highly sensitive detector to detect acoustic waves at resonance frequency, but the VO2 film was not of very high quality. In order to produce high quality VO2 mesa to be used for microcantilevers, VO2 thin films were synthesized using low pressure chemical vapor deposition technique (LPCVD) on AlGaN/GaN epitaxial layer on Si (111) substrate, and characterized using X-ray diffraction (XRD) and atomic force microscopy (AFM) to determine their material quality. Electrical and optical imaging methods were also used as characterization methods to determine the changes in properties due to the metal-insulator transition (MIT) of VO2. Resistance transition ratio before and after MIT transition was found to be > 1100, which indicates high quality of the material, suitable for a variety of sensing applications. Optical images taken before, during and after transition clearly indicate reflectivity changes caused by the MIT transition.